Reinforced building construction



Dec. 19, 1950 H. EDWARDS 2,534,580

REINFORCED BUILDING CONSTRUCTION Filed Oct. 18, 1945 5 Sheets-Sheet 1flilorn ey Dec. 19, 1950 I H. EDWARDS 2,534,580

REINFORCED BUILDING CONSTRUCTION Filed Oct. 18, 1945 '5 Sheets-Sheet 2mom/0710 /0 a 2 1 0 In men for ll/JVDE/Y [fin A1905 QZZM H. MI

5 Sheets-Sheet 3 In venior v ,mroilv 0WA6D5 b 5% u-Abaw fiilorn 6y Dec.19, 1950 H. EDWARDS REINFORCED BUILDING CONSTRUCTION Filed Oct. 18, 1945W OOOOOOOO 000000000 0000000 ooooooooo/ 000000000 aw 000000000 mmoo0000000 ooo00oo0o 0000000 5 Sheets-Sheet 4 H. EDWARDS 10. m flilorn e5In van for bwma/ [ow/W05 REINFORCED BUILDING CONSTRUCTION Dec. 19, 1950Filed Oct. 18, 1945 Dec. 19, 1950 H. EDWARDS REINFORCED BUILDINGCONSTRUCTION 5 Sheets-Sheet 5 Filed Oct. 18, 1945 5 W W w ZWJM H mm W pmlw nm i 1% fl Patented Dec. 19, 1950 UNITED STATES PATENT OFFICEaemroeopn BUILBEING coNsTRUcrroN Hayden Edwards, Columbus, Ohio aplicants Qctcher is, 1945, Serial No. 623 126 i i .Ciairns.

' The present invention relates to building constructions and moreparticularly it provides certain novel and useful forms of prefabricatedslabs, sheets or plates capable of forming the principal structure of awall, floor, roof or the like.

The principal objects of the invention are to provide structural andfunctional improvements in buildings and their erection and at the sametime to effect substantial economies.

These objects are accomplished mainly by providing an improved type ofbuilding unit in the form of a prefabricated slab or the like having aremarkably high ratio of strength to weight which can be manufactured byrapid and economicai rolling. stampin rpu chine r y the use of permanentmolds or other methods in- Volving the use .of dies and which is adaptedto be set up in accordance with any .of a great variety of architecturaldesigns quickly and inexpensively by relatively unskilled labor.

A, basic principle of the slab element is the use of a. skeleton type ofconstruction produced by forming the slab with numerous cavities,openings, channels and indentations which eiiect economy of material andreduction of weight.

,TIhis general rinciple is not new, since the prior .art aiiordsnumerous examples of building slabs of skeletonized form, generally madewith perforations or surface depressions, of various kinds.

the present invention which will now be briefly summarized- The slab,sheet or plate which forms a funda 1 mental element of the presentinvention, which will hereinafter be called a slab, comprises afoundation member in the form of a one-piece sheet or board skeletonizedby surface cavities which become closed, at the site where the slab isto be erected r installed in a building or other structure, by theaddition of closure elements which are made, and transported separatelyfrom the slab. In this way the handling weight of the originallyseparated elements of the completed slab-in-nla is materia ly reduced st at in .many cases an individua wo kman ca eas y lift the slab base,even when it is made in large dimensions, and mount it in position, al hu h the weight of the mnleted slab-in-place m ght be too gr at for saf oap d h nd i g w thou a helper or mechanical assistance. The open surfacecavities form cqnvenient seats for therecepe t on of the app in ooks ndth i of mechanical and hand hoisting instruments whenever it is found,necessaryor desirable to use such instruments.

. In additio to its su iiace ca es. the l b is provided with internalchannels or passageways which serve not only to reduce weight and savematerial but also to receive and enclose various utility conduits suchas pipes, wires, etc. An important feature of the invention resides inthe fact t at he e in rn ope in w ic x end in a number ofdirectionsthrough the slab body in a plane parallel to the flat surfacesof the slab, are so disposed that they can be formed in' the slab bymoldinglugsor.protuberances formed on d es or the lik an pr se nwa y iectio s no mal to the fiat s rfa of the sla Thus the use of a sand moldor other type of coring operation is rendere unnecessary, so that theslab can be fabricated in a permanent mold or by e trus o etwee c ntinuus y at o lers. or y on e o al tamp n p n h o even drop forgingoperations.

Th u face penings. whe c red as conemplat d in the set-up slab, fo a mup ic y of int r-commun cat ng l e cells t ro gh which atm pheric .a rmay be circula d t ae ate the s a o a wa l, floor. o r the l ma fr m apural ty o esla s- .In th Way the assembled slabs are kept wellventilated and dry.

In addition to their aerating function, the cells m y be used to clseheatine'. l li hting. airpurifying or other instrumentalities, inwhich s th el co rs are mod fied so as to beiheaa laced together.

It is also an objectof the invention .todispose cell caviti s in sla insuch. arrangement that r inforc g mesh may if des red be incorp rated inthe slab without protruding into the cavities.

Another object is to arrange all the surface cavities in such a way asto leave solid portions of the slab material substantially aligned so asto act as virtual joists or piers when the slab is used as a floor orwall.

General objects of the invention are to provide a novel slabconstruction which may be disposed in any conventional vertical,horizontal or pitched position in a building, bridge or other structure,so that great structural strength, lightness, durability and generalefiiciency will be provided at low cost.

The invention also provides means and arrangements for associating slabstogether in securely bonded relation, both as the components of anindividual wall, fioor, roof section or the like, and also as theadjacent members of two or more such sections.

Incidental objects are concerned with attaining novel lighting, heating,cooling, aerating and ornamental effects resulting from the use of aSingle basic type of slab skeleton base completed by the addition ofoptionally selected adjuncts such as cell cavity covers andinstrumentalities housed in the cells.

The principles of the invention are capable of being embodied innumerous specific forms, certain preferred examples of which are shownin the accompanying drawings in which Figure 1 is a front elevationalview of a slab constructed in accordance with the principles of theinvention, showing the interior surface, with the cell cavitiesuncovered, in the form in which the slab is produced by the casting orrolling operation;

Fig. 2 is a transverse sectional view of the slab taken along the line2--2 of Fig. 1, but showing the slab completed, ready for use as abuilding wall, with the cell cavities covered and with a sheet ofinsulating material applied to the exterior surface;

Fig. 3 is an edge elevational view of the completed slab;

Fig. 4 is an elevational view, similar to the view of Fig. 1, butshowing the exterior surface of the slab;

Fig. 5 is a transverse sectional view of the slab taken along the line55 of Fig. 1, at right angles to the View of Fig. 2, but like Fig. 2showing the slab completed by addition of cell cavity covers andinsulation and differing from Fig. 2 by showing a modified form offastening means.

Fig. 6 is a vertical sectional view through a portion of a buildingshowin wall in interior elevation and section and showing a floor insection, with utility conduits installed in the slabs;

Fig. 7 is a front elevation of a wall slab, or a top plan view of afioor slab, completed with cell cavity covers;

Fig. 8 is a front elevational view of a slab like that of Fig. 1,modified by inclusion of reinforcing, showin the interior surface of theslab completed by addition of cell cavity covers;

Fig. 9 is a front elevational view of the exterior surface of thereinforced slab shown in Fig. 8;

Fig. 10 is a view of the reinforced slab shown in Figs. 8 and 9, showingthe right hand edge of Fig. 9 in elevation;

Fig. 11 is a transverse sectional view of the reinforced slab shown inFigs. 8, 9 and 10, taken along the line llll of Fig. 8;

Fig. 12 is a view similar to that of Fig. 10 but showing an upper orlower edge of Fig. 9;

Fig. 13 is a vertical sectional view taken 4 through the junction of aWall and floor, showing a preferred manner of bonding slabs thereof;

Fig. 14 is a vertical sectional view taken through a wall and roof,showing preferred modes of bonding slabs in the roof sections and to thewall slabs;

Fig. 15 is a front elevational view of a slab like that of Fig. 1,showing the cell cavities formed on the exterior surface and covered bylenses;

Fig. 16 is a vertical sectional view taken through the walls of abuilding, near a corner thereof showing, in vertical transverse sectionand in interior surface front elevation, wall slabs having their outersurface cell cavities covered by lenses and having their inner surfaceslined with sheets having pockets closed by heat-transmitting covers;

Fig. 17 is a front elevational view like that of Fig. 15 but showing thecell cavities provided on the inner or outer surface and covered byplate glass panes;

Fig. 18 is a vertical sectional view like that of Fig. 16 but showingthe cell cavities and pockets provided with electric lighting, heatingor air purifying means and closed by fiat covers;

Fig. 19 is a transverse sectional view, like that of Figs. 5 and 11,showing a modified type of slab in which both surfaces are provided withcell cavities;

Figs. 20 and 21 are plan views of the opposite faces of a pair of floorslabs, or elevational views of the opposite faces of a pair of wallslabs, bonded edgewise together in place in a building or the like;

Fig. 22 is a transverse sectional view, taken along the line 22-22 ofFig. 21, through the joint of Figs. 20 and 21; and

Fig. 23 is a transverse sectional view through a slab showing theopenings in one of its surfaces closed by a filler applied in such a wayas to leave the internal passageways open.

However, it is to be understood that the particular embodiments shown bythese drawings and hereinafter explained are subject to furthermodification without departing from the broad principles of theinvention as stated in the foregoing outline of objects and as definedby the appended claims. It is also to be understood that not all of thefeatures incorporated in these specific embodiments need be used in theparticular combinations shown and described in this application forLetters Patent.

Referring now to the drawings, Figures 1 and 4 show respectively theinner and outer surfaces of one form of basic slab unit I embodying theprinciples of the invention. This form, as well as the others shown bythe drawings and hereinafter to be explained, is preferably made of anysuitable cementitious or analogous building material capable of beingpoured in a plastic condition and thereafter setting to rigid condition,by hydration or otherwise, such as Portland cement concrete, burnt clayor terra cotta, fused silica, or the asbestos fiber and cement materialnow widely used in the building industry and sold under various tradenames. However, the form of the slab is such that it is well adapted tobe made also of metal, as by die-casting, or by stamping or drop-forgingmetal sheet or plate stock.

The slab is so shaped that one of its surfaces, hereinafter designatedthe inner surface 2, is provided with a plurality of substantiallyhemispherical cell cavities 3 arranged in lines in such a way that thecavities of adjacent lines are staggered "relatively to each other, :asis -clearly shown in Fig. "1. Each cavity penetrates the slapsomefive-'sir'tl'is lmOl'e "or less of the slab thickness, so that'theopposite race 4 of the slab 'is'not broken by the cavity. However, thisopposite face is broken by "a relatively small aperture forperforation 5establishing communication between the face '4 and "the "centralbottommo'st point of the cavity. The surface 4 is alsointen rupted bygenerally rectangular shaped openings 6 which penetrate 'suflic'ient'lyinto the slab material to communicate with cylindrical "passageways Iwhich radiate from each cavity to con nect it with each adjacent cavity.*In the ar rangem'ent shown, each cavity has six such passageways 1,spaced "approximately =60" apart around each cavity, so that "all thecavities which are aligned "in any -'direction are connected by alignedpassageways I. This feature'I- regard as important because the alignmentof "the passageways facilitates fishing =utility conduits and the likethrough them.

In order to receive lids or closuresa's *will hereinafter be explained,each cavity is "surrounded by a widened rim depression forming ashoulder 8 set slightly below the plane ofthe inner wall 2 of the slab.v

The passageways I lie all in the same general plane, which is bestlocated parallel to and slightly outwardly from the median planeo'i theslab.

An important feature of the invention resides in the capacity'of theslab to be cast-or 'ro'lledby fixed, solid molding or roll surfaces, orto be punched, pressed or stamped from plain sheet or plate stock. Tothis end I make a ll'the cavities, passageways and openings in "suchformand relationship that all portions of all of them are directly open toone or another of the surfaces '2 and 4 of theslabby straight linesnormal to such surfaces. "This willbe evident from Fig. '2, where itwill be appreciated that a single --specially shaped moldingprotuberance or die projection maybe used to form each cavity 3 andthose portions of its six passageways 1 which are il'odated between eachdotted line -9 and the cavity, while another, differently shapedprotuberance or projection on a cooperating molding surface or die"forms the opening '6 and that "portion of the adjacent passageway "1which lies between the dotted lines '9. 0i course suitable projectionson oneor another of the two molding'or die surfaces will be provided 'toform the perforations 5.

The presently preferred material for the slab I is one o'f-the'cementitio'us or plastic type, and the drawings illustrate the saw inthe relatively thick form in which such "material' is best cast, moldedor rolled. *However, it istobe understood that cooperating dies,configured in the same way as the molding or rolling surfaces, may -beset up in a dropforging, "punching or stamping press and operated onplain 'meta'l sheets or plates of any appropriate gauge to produce 'ametallic slab of the same general surface and internal contours as thecemen'titious or plastic slab. The metallic slab can, however, be madesomewhat thinner, and it will 'be -found convenient in many cases tomake it longer "and/or wider :because the metal product can be handledwith'less danger of breakage, cracking or distortion.

It is thussapparent' thatthe particular arrangement hereinabovedescribed and shown in Figs. 1 "and 2 combines various functionalsurface de- 6 pressicns and internal passageways in a slap in suchawvay'thatthe slab need not beeX-pensively molded or cored :out but canbe cast by the use o ia permanent Torin or can be extruded betweenrotating rollers, or can be die-stamped, die-cast or'drop iorged.For-this reason coupled with the inexpensive material which may be used,the slab is extremely economical to make.

The slab isalso unusually light, since the ratio of its voids to itssolid material is very high. Notwithstanding this lightness, the slab isstructurallystrong because of the staggered arrangement of the 'lineso-fcavities which leaves a substantially straight or only slightly sinuousline of solid slab material running in one direction betweenadjacentrows of cavities. Two such lines are seen in Fig. l, o-ne'on-eachside ofthe vertical central line of cavities. These lines act in verticalcompression as virtual piers or studding when the slab is used "as awall, and when such lines "are disposed lengthwise between supports,when a slab is disposed horizontally, they act as 'virtual joists.

Thestructure thus far-described is made in one integral piece and is ofcourse very light because it is skele'tonized by the openings, cavitiesand passageways. It can be made light enough,-even when made in slabs ofappreciable length and width, for one workman to carry and sets. slabwithout'ass'istance. The'sur'fac'e openings-arcint'en'ded tobe coveredafter the slab is installed in a building or other structure, and thiscovering may'beaccomplished intwo principal ways which will now bedescribed.

The surface 2,which is generally and preferably employed as the interiorface of a building vvall, originally presents the series-of cavities3.These are covered by-discs it which more orless accurately fit "againstthe shoulders *8 and may be held in place in any convenient way, as bythe cement or other plastic keys indicated at H. Each-cover disc ill maybe made'in the form of a fairly thin circular plate cast, stamped orotherwise'formed from the same material as the slab itself or from anyother suitable material. A-s'lab completed'by the addition of coverplates [6 resents 'a'suriace "-2 which is continuous, unbroken andsubstantially smooth. If this surface be arranged as the interior of awall or as ace'iling it may be faced by plaster, wall'board or any otherconventional interior sheathing, or the slab and its covers iii may bemade with such accuracy as to present "a'sm'ooth, even, finishedsurface, as is W6l1 shoWn in Fig.7, which requires no plasteringor'other preparation prior to receiving adecorative finishof paper,paint or the like.

The surface '4 is brok'enby the openings i5 "and the small perforations5. It is generally desirable to'affix'sheet insulation, shown at l2' inthe drawings, to this surface when used as the exterior of 'awvall. "Onewayof accomplishing this aflixation is by inserting plugs l3 of anynailable material, such as wood, plastic or the like, into certain ofthe openings 56 and then nailing the sheets [2 to these plugs. Thus theexterior surface of the'wall is'finished, and o'f'courseany'conventional surfacing trim may be'app'liedsuch as stucco, boardsheathingor the like.

The slabs may be made in any convenient length and width, but it is bestto make their dimensions in multiples of each other and 'in multiples ofthe distance from center to center of the cell cavities. It will also befound desirable in most cases to provide two intersecting edgeso'feachslab with-a tongue f4 andthe other assmsq,

two edges with a complemental groove 15 so that adjacent slabs can beinterfitted together. Of course all the edges might be grooved and themating grooves of adjacent slabs be filled with some independent keyingmaterial.

A plurality of slabs, as cast, rolled or pressed in the skeletonizedform which has been described, are set edge to edge in vertical positionto form a wall, with the tongues it interfitted into the grooves l andwith the cell cavities 3 open to the interior surface. These cavitiesare then closed by the cover plates l6, and the exterior surface of thewall is sheathed by installing plugs l3 at selected intervals andnailing or'otherwise securing sheets of insulation i2 to these plugs.Optionally, the insulation may be mounted by means of bolts l5 passingthrough the perforations 5 and engaged with nuts and washers ll in thecells, as shown in Fig. 5, These bolts may be conveniently extendedbeyond the insulating material surface as shown in Fig. 5 as a means fortying exterior facing.

Fig. 6 illustrates a corner of a. building in which two intersectingwalls are formed of completed slabs and in which a floor is similarlyformed and tied into the walls. In this figure the bolts I6 are used tomount sheets of insulation, and furring it is interposed between theinsulation and any conventional type of exterior sheathing l9.

Fig. 6 also shows a convenient mode of supporting a floor, generallydesignated 28, on a wall, generally designated 2|. In this arrangementthe wall is laid up to desired height, so as to terminate in a singlecourse of slabs providing a continuous horizontal top edge surface. Thissurface provides a bearing for the margins of a floor slab which is laidon it, and the upper edge of this floor slab in turn provides a footingfor the course of slabs which are then laid up to continue the wall. Inthis way the floor is securely keyed into the wall.

It will be understood, with reference to Figs. 6 and 1, that the floorslabs are laid in such a way that the aligned cell cavities shownextending in vertical lines in Fig. l extend across the span between thewalls which serve as bearings for these slabs. Thus the solid slabmaterial, lying in almost straight lines between the aligned cellcavities, serves as virtual joists from bearing to bearing and rendersunnecessary the use of actual joists, beams or any other supportingmeans.

Fig. 6 also shows certain of the passageways I employed to house utilityconduits 22 which can easily be fished through those of the passageways1 which are continuously aligned in any direction. Thus, as shown inFig. 6, the conduits may extend in a vertical direction through thewalls, in a horizontal direction through the floor, or in any inclinedor diagonal direction through the floor or walls. These conduits may beled into or out of the wall through the surface 2, from any of thecavities 3, by omitting the cover disc Ill from such cavity or byproviding a hole in it, and'they may be led through the surface 4 fromany of the openings 6 or perforations 5.

When used as a floor I prefer to dispose the slabs with their cavitysurface 2 uppermost. The cavities may if desired be subsequently closedby covers It] to provide a foundation for any conventional type offlooring 23.

The surface 4 of the floor slab forms the foundation for a ceiling whichmay be built up in some such way as is indicated in Fig. 6, where asheet ofinsulation 24 is hung from the slab by f of the openings.

means of bolts 25 passing through some of the perforations 5. Thisinsulation may be covered by any suitable ceilin surface material, asindicated at 26, being fastened in place by the same bolts.

If desired or thought necessary, the quarterspherical or half cavitieswhich open to the edge of the top course of slabs in the wall 2| (one ofsuch cavities being shown at the top center of Fig. 1) may be filledwith cement to assist in bonding the wall and floor margins together.Such bonding is employed in Fig. 14 at 21 to secure together the twosections 28 of a pitched roof and also at 29 to secure the lower edge ofcavities and the adjacent floor half cavity as shown in Fig. 13.

Figs. 20 and 21 show the joint by which a pair of adjacent slabs arebonded together in a wall, floor or roof section. It will be observedthat the half-openings 6, open to the edges of the two slabs, becomealigned with each other and provide keyways for receiving fills 32 ofbonding material, preferably a cement introduced in plastic conditionand subsequently setting, thus providing a laced bond for the joint. Inorder to keep such plastic bonding material from filling the passageways'1 I form a shoulder 33 along the plane at which each opening 6 meetsthe adjacent passageway 1 along the long dimensions Plates 34 of somesuitable thin sheet material, which may be as inexpensive as cardboard,are laid on these shoulders to support the cement until it hardens andthus prevent it from entering and obstructing the passageways I. Ifdesired or thought necessary, the'joint can be strengthened by tyingadjacent slabs together by bolts or the like passed through the matingpassageways l which are intersected by the joint line.

Figs. 8-12 show a modification of the slab structure in whichreinforcing is incorporated. This reinforcing, designated 35, may takethe form of a series of wires or rods or coarse woven wire mesh sodimensioned that all the wires will lie in the solid portions of theslab and none of it will protrude into any of the cavities, passagewaysor openings. Such a reinforced slab is fabricated, installed andcompleted in the same way as has been described in connection with theunreinforced slab.

Fig. 19 shows a further modified type of slab in which both surfaces areprovided with open cavities 36. All the cavities are staggered withrelation to each other so that maximum strength of the skeletonstructure is preserved. Each cavity may be closed after the slab isinstalled by addition of a closure disc or plate It. Slabs made in thisform are primarily useful as the walls of structures which do notrequire insulation or other type of outer sheathing, and they are usefulalso in horizontal position as girders or as the floors of short spanbridges, culverts and the like, or in horizontal or pitched position asa roof, in all of which uses some plastic surfacing material oan beinserted or poured into the cavities after the structure is mounted inplace. In this way the weight of the slab or the like is kept low forease in handling, transportation and installation.

Figs. 15 and 16 show a modification in which slabs used to form wallsare positioned with their cavity surfaces 2 on the outside and in whichassum the. cavities,- are, closed; by double convex lenses 31'eachheldinplace against the shoulder- 8 by some such. means; as.v a,bezel. These lenses. concentrate, solar rays at focal points in: thecavities where the heat is absorbed; by an appropriate fluidin oneterminal; portion, 38 ofa coi139 which extends through the perforation5; at the base of the cavity and terminates in a portion on or in theyinterior surface of; the. wall. It is convenient to mounttheterminalportion 40 of'each coil in a pocket 4| f'ormediin interior wallsheathing and covered by a perforated closure plate 42. Heat generatedin the coil is thus transmitted through, the wall and; into the.interior of the building by' passing; through, the perforations in,time.v plates, 40,.

The coils may be connectedinseries witheach other and, with a, pumpandreservoir in which sun heat, canbestored for recirculation aftersundown.

Figs. 17' and 18 illustrate a further modification in, which transparentor translucent panes 43; are substituted for the lenses 31' and for theperforated closure plates 42; Such' awall is intended to be impermeableby heat and air and" hence may include a sheet; of" insulationinterposed between the wall slab and its outer sheathing 44, closing theperforations 5;. Electric light bulbs 45 and 46 may be positioned inthe, sheathing pockets 4| and in the cavities 3 to give variousilluminating effects to both the'insid'e and outside surfaces of" thewalls Such a wall, and of course also a ceiling similarly constructed,may be used in the form of. an isolated panel to give novel effect to astore front, theater lobbyor the like, or the interior surfacearrangement may be employed with a plainexterior, made as in; Fig. 6,"to provide ceiling or wall lighting.

For the illuminating bulbs of Fig. 18 there, may be substitutedultra-violet ray bulbs or their equivalent for, sterilizing the; air inthe. cavities,

and thisv air may be circulated, by way of the In. all forms of theinvention, the slabs which are associated in edge to, edge relationprovide continuous communicating passageways. through them. I haveexplained that. any set of such passageways which are aligned in anydirection may be: selected to house, Wiring, piping orthe. like. Thesepassageways andthe, remaining ones may-beused also to conduct. heated orcooled air through. the walls from some point. or level selected as aninlet to some other point or level serving as; an outlet. It will,readily be appreciated that walls, ceilingsaor'floors may in this wayhave their temperature modified and. controlled, in: any desired way.The warmed or cooled air may be recirculated from the passageways to aheating orrefrigerating means andv bacle: again to the passageways, orit maybe exhausted into thebuildinginterior or to the outside, in anyway desired, It; is recognized, also that. the. cell. cavities may,havelm un ediinqthem individual heat radiators, such as those of theelectric filament type, which will warm theslabs and; theair contained;in them, and that this-air may; be kept out of, the building interior bythe useofimperforate closure discs ID, or it may be discharged into thebuilding interior by the use of perforated discs 42. Obviously,individual cooling coil units, may-be substitutedfor theheating;elements. A desirable arrangement would include the use of bothheatingand cooling; units disposed in different selected cells foroperation at different seasons of the year.

It is thought: to be clear from the foregoing description and, the,drawings that the slab provided by the invention may be embodied in theform, of a single standard type of skeletonized body to which any of thevariety of cell cavity covering elements i8; 31 42', 43, or others maybe selectivelyappli'edi While I prefer to make the cell cavitiessubstantially hemi-spherical as 20" adapted to be impressed inthebasi'cmaterial of the bodybydie protuberancesin casting, rolling,forging, stamping and like processes.

In the appended claims, which point out the broadly novel principles ofthe invention the term building walls and the like" is intended toinclude not only vertical walls properly so called; whether bearing,non-bearing or backup, but also such elements as floors, roofs,ceilingsand' the like, and the utility of the-invention is not limitedto buildings per se but is recognized: as being applicable to suchanalogous structures as bridges, decking, bulkheads, etc. The inventionis broadly capable of being' embodied in numerous forms other thanthosespecifically illustrated and described in the foregoing specificationand thedrawings and all such modifications are intended to be coveredby; the broaderof the appended claims.

I claim v 1. A building slab comprising a skeletonized body having eachof two opposed outer surfaces provided with a set of indentations havingtheir inner portions staggered with relation tothe inner portions of theindentations of the other set and intersecting said inner portions, theinterior of said slab being provided with passage- .ways formed by saidintersecting portions and extending laterally through the body andthrough the end Walls thereof in a plane parallel to the indentedsurfaces.

2: A building slab; comprising a skeletonized body having each of twoopposed outer surfaces provided with a set of; indentations having theirinner portions staggered, with relation to the inner portions of theindentations, of the other set: and: intersecting said, inner portions,the interior' of said slab being provided with passageways formed bysaid intersecting portions and extending laterally through the body andthrough the end walls thereof in a plane parallel to the indentedsurfaces, in combination with closures for covering said indentations.

3. A building slab comprising a skeletonized body having each oftwoopposed outer surfaces provided with a set of indentations having theirinner portions staggered with relation to the inner portions of theindentations of, the other set and; intersecting said inner portions,all points. on the bottom. of each indentation of each set lyingdirectly beneath points within said in- 31 dentation in the plane of oneof said surfaces, whereby none of said bottoms is directly covered byany of the material of the body between said bottom and one of saidsurfaces, the inner portions of the indentations of each setinterseeting the inner portions of the indentations of the other set,and the interior of the slab being provided with passageways formed bysaid intersecting portions and extending laterally through the body andthrough the end walls thereof in a plane parallel to the indentedsurfaces, where- ..by all of the indentations can be formed by dieprojections pressed vertically to the planes of said surfaces.

in which the closures for said indentations are in the planes 7 of saidrespective surfaces, leaving said passage- -ways unobstructed.

1. The slab claimed in claim 2,

said indentations being open to an edge of the slab in angularlydiverging relation, whereby two similar slabs may be laid edge to edgein stag- .gered relation with an indentation of one pair formed in oneslab aligned with the corresponding other indentation of a pair formedin the other slab so that the aligned indentations combine to provide aplurality of openings crossing the line of joint between the two slabsat alternately different oblique angles and are adapted to receive andhold keying material to bond the two slabs together and by theirdifferent angularity to the line of joint resist separating forcesnormal to said line.

7. The slab claimed in claim 1, in which certain of the indentationsformed in one oi. said surfaces have spaced parallel side wallsintersecting the edges of the slab, adjacent pairs of said indentationsbeing open to an edge of the slab in angularly diverging relation,whereby two similar slabs may be laid edge to edge in staggered relationwith an indentation of one pair formed in one slab aligned with thecorresponding other indentation of a pair formed in the other slab sothat the aligned indentations combine to provide a plurality of openingscrossing the line of joint between the two slabs at alternatelydifferent oblique angles, in combination with closure plates 1 disposedin the aligned indentations bonding the I two slabs together and bytheir diiferent angularity to the line of joint resisting separatingforces normai to said line.

8. A building slab comprising a body having separated substantiallyhemi-spherical cavities formed in one surface in a plurality of parallellines with the cavities of laterally adjacent lines staggered withrelation to each other and having its opposite surface provided withrectangular indentations arranged in groups extending in directionsradiating from the axis of each of the cavities which is normal to theplane of the first named surface, said indentations intersecting saidcavities and the intersections forming passageways extending laterallythrough the body and radial relatively to the cavities and establishingcommunication between ad acent cavities.

9. The slab claimed in claim 8, in which the cavities and indentationsare closed by separate individual covers disposed between the bottoms ofthe cavities and indentations respectively and the adjacent surfaces ofthe body, leaving the passageways open inside the body.

10. A building slab comprising a body having separated substantiallyhemi-spherical cavities formed in one surface and having its oppositesurface provided with rectangular indentations arranged in groupsextending in directions radiating from the axis of each of the cavitieswhich is normal to the plane of the first named surface, each of saidindentations extending into and intersecting a pair of adjacentvcavities and the intersections constituting passageways wholly withinthe body establishing communication between adjacent cavities.

11. The slab claimed in claim 10, in which ad. jacent pairs of thepassageways are aligned so that utility conduits can be projectedthrough the interior of the body.

12. The slab claimed in claim 10, in which six indentations radiate fromeach cavity and opposite pairs of passageways of the same group arealigned so that utility conduits can be projected through the interiorof the body in any of three different straight line directions.

13. A building slab comprising a cementitious bodyhaving a plurality ofspaced separated cavities formed in one surface and arranged in parallellines with the cavities of adjacent lines staggered relatively to eachother, in combination with elongated metallic reinforcing elementsembedded in the body in straight lines between adjacent cavities.

A building slab comprising a cementitiou body having a plurality ofspaced separated substantial helm-spherical cavities formed in onesurface and arranged in parallel lines with the cavities of adjacentlines staggered relatively to each other, in combination with elongatedmetalc reinforcing elements embedded in the body in straight linesbetween adjacent cavities.

HAYDEN EDWARDS.

REFERENCES CITED The following references are of record in the file ofthis patent:

v UNITED STATES PATENTS Number Name Date 528,636 Kupper Nov. 6, 1894689,523 Trumbull Dec. 24, 1901 706,974 Lyle Aug. 12, 1902 783,448Merrill Feb. 28, 1905 836,017 Douglass Nov. 13, 1906 901,833 Rettig Oct.20, 1908 995,940 Meier June 20, 1911 1,043,701 Freeman Nov. 5, 19121,171,191 Gronert et al Feb. 8,1916 1,277,829 Baum Sept. 3, 19181,305,294 McIntyre June 3, 1919 1,597,167 Pace Aug. 24, 1926 1,670,095Boes May 15, 1928 1,991,459 Slayter Feb. 19, 1935 2,908,370 SchwalbeJuly 16, 1935 2,196,177 Hultquist Jan. 25, 1938 2,298,001. Fay Oct.6,1942

FOREIGN PATENTS Number Country Date 5,352 Great Britain of 1899 278,299Germany of 1914 739,273 France of 1932

